Internal-combustion engine.



G. K. DAVOL.

INTERNAL COMBUSTlON ENGINE.

APPL|CAT|0N FILED FEB. 21.1910. 3,9@59720 Patented May 8, 1917.

3 SHEETS-SHEET 1.

Flai.

WTNESSES:

ATTRNEYS G. K. DAVOL.

INTERNAL coNlusTloN ENGINE.

APPLICATION FILED FEB. 2l. 1910.

Patented May 8,1917.

3 SHEETS-SHEET 2 NI/ENTUR. Berge Kn Davnl .1 mm-H Al 7M FIG. Z.

W'T/VESSES:

ATTORNEYS G. K. DAVOL.

INTERNAL COIVIBUSTION ENGINE,

APPLICATIN FILED FEB. 21.1910.

Patented May 8, 1917.

3 SHEETS-SHEET 3.

JIHIENTOR.

E [IP QE K I DEV DI H/TNESSES:

A TToR/VEYS GEORGE K. DAVOL, 0F SAN FRANCISCO, CALIFORNIA.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

llatented May 8, 1911"?.

' Application led February 21,1910. Serial N o. 545,029.

To all whom t may concern:

Be it known that I, GEORGE l. DAvoL, a citizen of the United States,residing in the city and county of San Francisco, in the State ofCalifornia, have invented a new and useful Form of Internal-CombustionEngine, of which the following forms a specification.

My invention relates to an improved means for lubricating and coolinginternal combustion engines.

Two of the greatest sources of diliculty and trouble in internalcombustion engines of the ordinary type, lie in the necessity forcoolino' and lubricating the cylinder walls.

Ordinarily the cylinder walls are kept cool by water jackets surroundingthem and lubricated by the use of the special oils.

In large engines having cylinders with very thick walls the waterjackets become less effective, while the lubrication of internalcombustion engine cylinders by means of oil, gives rise, owing to thehigh temperatures, to many troubles and difficulties which it is notnecessary to here enlarge upon.l

Especially are such troubles encountered when the utilization of dustyor very impure gases is attempted.

My invention is intended to provide an internal combustion engine vinwhich the working piston does not touch the walls of the cylinder inwhich it reciprocates, but is separated therefrom by a very minuteannular space.

In order to make the piston tight, or prevent the escape of gasesthrough this annular space, water is introduced between the cylinderwalls and piston, filling the annular space and preventing the egress ofgases before the water itself has been eX- pelled.

The water so introduced is intended 'to also serve as a cooling medium,to keep the temperature of the cylinder walls and piston within properlimits.

The water being introduced on the inside of the cylinder walls and inactual Contact with the piston, performs its cooling functions mosteffectively.

I am aware that internal combustion engines have been constructed inwhich the surface of a body of water is presented to the burning charge,and made to receive the pressure of the working gases and transmit thepressure to a plunger or piston.

In the engine embodying my invention, however, the water is not used totransmit the pressure of the working gases to the piston, but the gasesact directly on the piston, and the Water is only used for cooling andpacking purposes, or to prevent the escape of the gases, and inconnection with a piston or plunger which does not touch the walls ofthe'cylinder in which it reciprocates.

As the piston does not touch the walls of the cylinder in which itreciprocates, it must be very accurately guided; and the means employedto guide the piston, as well as a design which shall permit, underpractical conditions of the necessary accuracy of construction become 0fgreat importance.

In this engine, the most impure and dusty gases, crude oils andulverized fuels, may be used without trou le arising from. cylinderlubrication.

In the accompanying drawings:

Figure l shows a vertical section taken onthe center line of the engine,the plane of the section being at right angles to the crank shaft.

Fig. 2 shows a vertical section taken on the center line of the engineat right angles to the sectional view shown in Fig. l.

Fig. 3 shows an enlarged vertical sectional view of the piston,cylinder, and a portion of the cylinder head, the view being taken onthe same sectional plane as that of Fig. 2.

Fig. 4 shows a horizontal section taken on line c--x Figs. l, 2 and 3.

All parts shown in the various views are designated by the samereference numbers in all the views.

Referring to the various drawings, l is the main frame of the enginewhich is mounted on the bed plate 2, which carries the crank shaft 3 inthe bearings 4.

The frame l, which I shall also term a guide cylinder, is boredthroughout the greater portion of its length very accurately and forms acylindrical guide or slide, in which reciprocates a slide or pistonguide 5.

The piston guide 5 is accurately finished to lit within the guidecylinder with but very little clearance.

The piston guide 5 carries the wrist pin 6 which is connected to thecrank pin of the Shaft 3 by means of the connecting rod 7.

The working cylinder 8 is accurately centered within the guide cylinder1 and is attached thereto by a flange at its upper end.

The working piston 9 is attached to the piston guide 5 by a. flange atits lower end and is accurately centered within the piston guide.

As seen in the Figs. 1 and 2 the piston 9 enters and reciprocates withinthe cylinder 8, but is made of slightly less diameter than the insidediameter of the cylinder, and being guided and held by the piston guide5, does not touch the cylinder, but 1s separated therefrom by a minuteannular space, which space is too small to be shown 1 n Figs. 1 and 2,while in Fig. 3 the space '1s shown and is somewhat exaggerated 1n orderto make it apparent.

The piston guide 5, it is seen extends up almost as high as the end ofthe piston 9, which is important, for if the piston 9 extended up muchhigher than the piston guide, thenv any slight lateral movementpermitted the end of the piston guide 5 would be allowed the extendedupper end of the piston 9 to an increased or multiplied extent, so thatit could not be guided so accurately.

The piston guide 5 is therefore made long and is made to almost whollyembrace or cover the whole length of the piston 9. This necessitates theconstruction shown, of having the upper end of the piston guidepartially surround the cylinder 8 at the upper end of the stroke.

Above the cylinder, is the cylinder head 10 which is held in place bybolts which A pass through its lower ange and through Vthe anges of thecylinder 8 and guide cylinder or frame 1, holding them all in properrelative positions.

The cylinder head has a water jacket 11 for cooling purposes, and alsoan annular water passage 12 through which the packing and cooling wateris supplied to the cylinder.

This water passage 12 is connected with a pump 13, Fig. 2, by means ofthe pipes 14 and check valve 15.

The pump 13, which is operated Vfrom the eccentric 16 draws waterthrough the suction pipe 17 and check valve 18 and forces it at eachrevolution of the crank Shaft into the water passage 12 in the cylinderhead. To simplify the. drawing the check valves are not shown insection.

From the annular water passage 12 the water is forced into the cylinderand against the cylinder walls through a number of small holes ornozzles 19, Figs. 1, 2 and 3.

that at'the upper end of the cylinder there 1s an increased annularspace between the cylinder and piston when the piston is at the top ofits stroke.

`This counterbore may be made cylindrical with straight sides orconical. The conical form is shown in the drawings.

The holes 19 are drilled on a circle so that their edges come flush withthe edge of the col'mterbore so that the issuing jets of water.

come immediately in contact with the walls of the cylinder orcounterbore.

The packing and cooling water supplied by the pump 13 is, as beforestated, forced into the cylinder and against the cylinder walls at eachrevolution and this injection of water is-probably best effected if doneduring the compression or upward stroke of the piston. I

The water issuing from the small holes 19 rushes down along the cylinderwalls and as the piston rises, ills the annular space between piston andcylinder and accumulates in the enlargement of the annular space at theupper end of the cylinder. This water under the pressure of compressionand afterward under the pressure of the working stroke, is, of course,continuously escaping at the lower end of the cylinder, but the annularspace through which it must escape is so small that the amount so lostdoes not constitute a serious loss of -pressure or work.

To further obstruct the escape of water at the lower end of the cylindera number of grooves 20 are formed in the cylinder walls and the eddyingeEect produced by these grooves appreciably reduces the amount of waterlost.

It will be seen that the head of the piston is shaped with its edgesbeveled off at an angle, which in the figures is approximately 45. Thisshape is given the piston so that on its rising stroke any water meetingthel piston is, through the inertia of the water and the speed of thepiston, thrown off against the cylinder walls or into the annular spacebetween cylinder and piston. It willV be seen that if the end of thepiston was finished off straight across, without such beveled edges,then water might be caught on the top of the piston and projected intothe compression space above the piston at the top of the stroke.

At the lower end of the cylinder is formed an exhaust passage 21, Figs.1, 2 and 3, which exhaust passage or port the piston 9 overruns oruncovers at the lower end of its stroke, permitting the free egress ofgases and water from the cylinder.

The position of the top of the piston at the lower end of its stroke isshown in dotted lines in Figs. 1 and 2.

mesma piston andiprevent its escape except through the exhaust passagesprovided, the lower edge of the exhaust port 2l is made sloping down andaway from the piston forming a sharp upper edge 23. y

An additional groove 24: is formed in the cylinder wall below this edgeand\is connected with the exhaust passage by small inclined passages 25,see Fig. 3.

This groove is designed to catch water adhering to the piston and leadit into the exhaust. A number of-such grooves may be employed ifdesired.

The exhaust passages 22 connecting at each side with the exhaust portpass out through openings found in the walls of the guide cylinder orframe 1, as shown in Figs. 2 and 4.

It is also seen that the'upper part of the piston guide is recessed orcut away at each side, in order to clear these exhaust passages at theupper end of the stroke. The manner in which the piston guide is so cutaway is shown in dotted lines in Fig. l and is also shown in section inFig. 4.

The form of engine illustrated ,in the drawings and so far described asembodying -my invention is a two-cycle engine, in

which the charge of air is first drawn into the crank case, by theupward stroke of the piston and piston guide, through the open-y ing 26which is covered on the inside by the flap valve 27, Fig. l. At the topof the stroke the inlet ports 28 are uncovered by the edge of the pistonguide and additional air may s0 enter the crank case.

On the downward stroke the air so entrapped 'in the crank case islightly compressed by the descending piston guide and piston and lillsthe air passage 29 leading to the cylinder head 10 and valve chamber 30.

Vhen the exhaust port 2l is uncovered by the piston at the lower end ofits stroke the pressure within the cylinder is released and falls tothat of the atmosphere. Then the pressure of the lightly compressed airin the crank chamber and above the automatic inlet valves 3l in thecylinder head causes the said inlet valves to open and the lightlycompressed air charge flows through from the crank chamber and passage29 into the cylinder. v

On the upward stroke the valves 31 auto-f matically close and the chargein the cylinder is compressed.

Fuel may be added to the air charge in the form of gas at any convenientpoint,

within the crank chamber, or within the passage 29, or it may bedirectly injected into the cylinder through the pipe 32 in the cylinderhead, at any suitable time during the compression stroke or afterward.

Liquid fuel or pulverized solid fuel may be similarly injected.

1 have not considered it necessary to show any injecting apparatus forthis purpose as that is a feature which does not essentially bear uponmy invention.

Ignition is accomplished in the usual way as by a spark plug 33 shown inFig. 2.

aving lnow described my invention as embodied in an engine working on'the two stroke cycle, l will say that it is applicable to an engineworking on the four stroke cycle with 4certain additions of parts whichdo not directly bear upon the invention.

I consider, however, that my invention can be embodied with particularadvantage in an engine operating on the two stroke cycle.

The manner in which the packing and cooling water is supplied to thespace between the cylinder and piston is not confined to that shown inthe drawings and just described.

The water may, if desired, be supplied in a continuous stream, and notintermittently as by the action of a pump such as shown and described.It may be supplied from any suitable source either continuously4 orintermittently.

The essential requirements are that the piston be guided within thecylinder so that it shall not designedly touch the walls of thecylinder, but shall be separated therefrom by an annular space, and thatthis annular space be supplied with water, in order to hold back orretard the escape of gases through the said space, and that sufiicientwater be supplied to the inside surface of the cylinder to eii'ect therequired cooling.

For the 4cylinder and piston which will be subject to the corrosiveaction of the water, suitable special materials should be used which arenon-corrosive. Nickel steel carrying a high percentage of nickel,certain bronzes, or the metal known as Monel metal being an alloy ofcopper and nickel, would be suitable.

The engine embodying my invention can be most advantageously made vofthe vertical type, as in a vertical engine the draining of the waterfrom the cylinder is easily accomplished. It is, however, not anabsolutely necessary requirement that the engine be made vertical. Ayslight inclination from the vertical would have very little efiect. Inthe claims the use of the word vertical is intended to meansubstantially vertical, and to cover any small inclination or deviationfrom the vertical.

For ease or practioability of manufacture, and practicability ofoperation, the working cylinder is accurately concentrlc with the guidecylinder, and the workmg piston concentric with the pistolrguide, andthese parts are referred to as being so concentric in the claims. Aslight departure from this concentric arrangement, however, would notaffect the essence of my invention and is intended to be covered by mydes1gn and invention.

In the specification and in the claims which follow, I have used theterm an annular space to describe the clearance between the piston andthe cylinder, and have further used the term free to describe thisclearance.

I wish to make it clear that although I consider these terms strictlycorrect as defning the clearance or space, which is purposely andcarefully provided for, still 1t must be understood that this space orclearance may be extremely small. I endeavor to provide a free clearancebetween the piston and the cylinder, and to avoid actual contact, andstill keep this clearance very small. With accurate workmanship thenecessary conditions can be fullled, and the piston and the cylinder bekept out of contact. This clearance between the piston and the cylinderwalls, when the piston is exactly centered within the cylinder, shouldpreferably be less than ten thousandths of an inch in an engine having apiston twelve inches in diameter.

The term cylinder or working cylinder as commonly understood and used inthe specifications and in the following claims is intended to designatethatpart in which the piston reciprocates and which maintains with thepiston gas tight relations, resisting the pressure of the working gasesand acting to ,confine them against esca'pe, and forming with the pistona gas tight chamber of variable volume, which may or may not be ofcircular cross section.

Inasmuch, therefore, as the cylinderin the strict and proper sense,constitutes -only that part which resists the pressure of the workinggases and maintains with the piston substantially gas tight relations,it will be understood that that part encircling the piston below theexhaust port 21, which has hereinbefore been referred to as part 'of thecylinder walls, although associated with the working cylinder, and inthe construction shown in Figs. 1, 2 and 3 being actually formed of thesame casting, is not required to resist the working pressure of thegases and does not in the proper sense which is intended and explainedabove, form part of the working cylinder. It must, therefore, berecognized that the part referred to, which is separated from thecylinder by the open exhaust passage and the principal function of whichis to confine the exhaust gases, could, if desired, be allowed to' be insliding contact with the plston, w1thout 1t being considered a contactbetween the plston and the working cylinder. In my preferred arrangementas shown in Fig. 3 this part does not touch the piston but is separatedtherefrom by the same clearance that separates the piston from thecylinder proper.

It is to be understood that the grooves 20 shown herein as formed in thecylinder constitute a labyrinth packing, provided to retard the flow ofwater between the -piston and the cylinder, and that substantially thesame effect is produced whether the grooves be formed in the piston orin the cylinder, as a result of which I desire to claim any sucharrangement of labyrinth packing equivalent to that shown for securingthe result referred to.

I desire to make it clear that in these specifications and claims, theterm Water is intended to mean water, or an equivalent liquid. I preferpure water, but my invention is intended to cover any other suitableliquid or solution or emulsion, which either through design or necessitymay be used.

It is to be understood that while I have shown my invention as appliedto a two cycle engine, in which the exhaust portv is controlled directlyby the engine piston, I do not limit myself to this particularconstruction, but may employ other types of engine and other valvemechanisms without departing from the spirit of my invention.

What Iclaim is:

1. In an internal combustion engine, the combination of a cylinder inwhich expansion of the working gases takes place, a piston guided toreciprocate within but not in contact with the said cylinder beingseparated therefrom by an annular clearance, the said clearance beingopen or unconned at the open or crank end of the cylinder, and means forsupplying water to the said clearance.

2. In an internal combustion engine, the combination of a cylinder inwhich expansion of the working gases takes place, a piston guided bymeans external to the said cylinder to reciprocate within butnot incontact with the walls of the said cylinder, said piston being separatedfrom said cylinder by a free annular space open or unconfined at theopen or crank end of the cylinder, and means for introducing water intosaid annular space.

3. In an internal combustion engine, the combination of a workingcylinder, a piston guided to reciprocate within but not in contact withthe walls of said cylinder being separated therefrom by a free annularspace,

said annular space opening freely at its outer end to an exhaustpassage, and means for introducing Water into the said annular space.

4. In an internal combustion engine, the combination of a cylinder inwhich expansion 0f the Working gases takes place, a piston guided bymeans external to the said cylinder to reciprocate Within but out ofcontact with the Walls of the said cylinder' being separated therefromby an annular clearance, the said clearance opening at its outer end toan exhaust passage, and means for introducing Water into the saidannular clearance. j

5. In an internal combustion engine the combination of a cylinder inwhich expansion of the Working gases takes place, a piston guided toreciprocate Within but not in contact with the said cylinder beingseparated therefrom by a free annular space, means for introducing Waterinto the said annular space, and a plurality of substantially parallelunconnected grooves between the piston and cylinder for receiving saidwater and producing eddy currents therein.

6. In an internal combustion engine, the combination of a cylinder inwhich expansion of the Working gases takes place, a piston guided toreciprocate Within but not in contact with the said cylinder beingseparated therefrom by a free annular space, means for supplying Waterto the said annular space, and an annular exhaust port into which thesaid annular space opens.

7. In an internal combustion engine the combination of a cylinder inwhich expansion of the Working gases takes place, a piston guided toreciprocate Within but not in Contact with the said cylinder beingseparated therefrom by a free annular space,

means for introducing `vvater into the said annular space, and anannular exhaust or relief port formed at one end of said cylinder, saidport being opened and closed by the movement of the said piston.

8. In an internal combustion engine, the combination of a cylinder inWhich expansion of the Working gases takes place, a piston guided toreciprocate Within but separated from said cylinder by a free annularspace, said cylinder having an exhaust or relief port or ports at oneend, said port or ports being opened and closed by the movement of thesaid piston, and means for introducing Water into the cylinder at theother end.

9. In an internal combustion engine, the combination of a substantiallyvertical cylinder, a piston guided to reciprocatein said cylinder andseparated from the lnslde surface thereof by an annular space, anannular exhaust port formed at the lower end of the cylinder, and -meansfor introducmg waterinto said cylinder at its upper end -combination ofa cylinder in which expansion of the Working gases takes place, a pistonguided to reciprocate within but separated fromthe said cylinder by afree annular space, and means for introducing Water into one'end of thesaid annular space, and delivering it from the other end of said Spaceat each stroke of the engine.

11. In an internal combustion engine the combination of a cylinder inwhich expansion of the Working gases takes place, a piston guided toreciprocate Within but separated from the cylinder by an annular space,said cylinder having an annular Water collar at its inner end providedWith a plurality of separate outlet openings to direct issuing jets ofwater onto the inside surface of said cylinder, and means for supplyingWater to said annular collar.

12. In an internal combustion engine, the combination of a cylinder, aworking piston reciprocating Within but separated from said cylinder bya free annular space, means for sealing the said annular space withWater, a cylindrical piston guide of larger diameter' than said Workingpiston, and a guide cylinder adapted to hold and guide saidpiston guideand piston, the space above the said piston guide being in opencommunication with the atmosphere.

13. In an internal combustion engine the combination of a guidecylinder, a working cylinder concentric Within said guide cylinder, saidcylinders being joined at their upper ends, a piston guide slidingwithin said guide cylinder and reciprocating at its upper end Within thespace between said cylinders, a Working piston attached to and guided bysaid piston guide, said Working piston reciprocating within said Workingcylinder and separated therefrom by a free annular space, and means forsupplying Water into the said annular space.

14. In an internal combustion engine, the combination of a guidecylinder, a Working cylinder in Which expansion of the Working gasestakes place, said cylinders being joined at one end and the Workingcylinder concentrically disposed Within the guide cylinder, acylindrical piston guide, a piston attached to and concentricallydisposed Within the piston guide, said piston guide reciprocable Withinand in sliding contact with the guide cylinder, and said pistonreciprocable Within said Working cylinder and out of contact therewith,and means for introducing Water into the space separating the saidWorking piston and Working cylinder.

15. In an internal combustion engine, the combination of a guidecylinder, a Working iis cylinder concentrically disposed within thewalls and an outlet passage or passages leading laterally from saidworking cylinder through the walls of said guide cylinder, a pistonguide reciprocating within said guide cylinder, and a working pistonattached to said piston guide and reciprocating withiny but not incontact with said working cylinder, said piston guide reciprocatingWithin the space between said cylinders and cut away to clear saidoutlet passage or passages.

16. In a two stroke internal combustion engine the combination of aguide cylinder, a working cylinder concentrically disposed within saidguide cylinder, a cylindical v piston guide tting and reciprocatingwithin and in sliding` contact with Said guide cylinder, a workingpiston of smaller diameter than and attached to said piston guide andreciprocating within and separated by an annular space from said workingcylinder, means for introducing water into the said annular space, and aclosed crank case opening into said guide cylinder, 'said piston guidebeing adapted to draw in and compress air or gaseous charge within thesaid crank case.

17. In an internal combustion engine, the combination of a cylinder inwhich combustion and expansion of the working gases takes place, apiston guided to reciprocate within but not in contact with the Walls ofthe said cylinder being separated therefrom by a free annular space, thesaid space open ing at its outer end to the atmosphere or exhaust, andmeans for introducing water into the said annular space to cool the saidparts and prevent the'egress of theY Working gases.

18. An internal combustion engine having in combination, a piston, acombustion chamber unprovided with packing, in which chamber the pistonreciprocates, guides eX- terior to said chamber for guiding the pistontherein, an exhaust Iport, ythe piston having a diameter onlysuiiiciently smaller than the diameter of the encircling Walls to'provide a water seal between the combustion chamber and exhaust port,and means to supply water between the piston and the walls. n

19. In an internal combustion engine, a Working cylinder, a pistonmovable within said cylinder, but of a diameter substantially smallerthan said cylinder so that said piston and cylinder are out of contact,said piston being unprovided with packing ring, a Water seal betweensaid cylinder and said 'piston, a restricted annular space being formedbetween said piston and the bottom of said cylinder, in which saidannular space said water seal is maintained.

In witness whereof, I hereunto subscribe my name this 16th day ofFebruary, A. D.

GEORGE K. DAVOL. Witnesses JOHN HAMILTON, MILDRED SCHINNELLER.

